Outgoing West Australian Senator Louise Pratt has launched a blistering attack on her Labor colleague Joe Bullock, labelling him a “deeply homophobic” person who is disloyal to his own party, and calling for urgent reform of the WA branch of the Labor Party.

In an emotional press conference in Perth, Ms Pratt has admitted it is “increasingly clear” that she will lose her place in the Federal Parliament as the ALP will not hold its second Senate seat in WA.

It comes despite her warnings to the party's executive not to award Joe Bullock the top spot on the Senate ticket, believing it would be disastrous for Labor’s fortunes.

Backed by a small crowd of supporters, Ms Pratt called for urgent reform of the WA branch of Labor, which she described as the “least democratic of all the nation’s ALP branches”.

“It is increasingly clear the the ALP will not hold its second Senate seat here in WA,” Ms Pratt said.

“Clearly this is a very difficult realisation for me, and for the Labor Party.”

Senator Pratt was forced to take the No.2 position on Labor's Senate ticket to make way for Mr Bullock for the recent WA senate elections.

It was part of a factional deal between the Right-aligned Shop, Distributive and Allied Workers Union (SDA) and the Left-aligned United Voice union.

Senator Pratt was scathing of the way Mr Bullock was installed, blaming the debacle for Labor’s plummeting support.

She also says his views on social issues sit on the fringe of Australian culture.

“It is a blow to progressive voters that I would be replaced in the Senate by someone who I have known for many years to be deeply homophobic, to be anti-choice and, [who] has recently emerged, disloyal to the very party he bas been elected to represent,” she said.

“Far from my views on these issues being fringe as he has claimed, it is Joe Bullock and other members of the SDA leadership who are on the fringe of mainstream views.”

Ms Pratt called for reform of the Labor Party, saying she was ashamed of the factional deal that installed Mr Bullock in the top spot.

“It goes to the heart of the need for reform … of the Labor Party,” she said.

“We know the SDA has a large voting bloc within the Labor Party. The leadership of the SDA have consistently used their bloc to preselect members of parliament who are anti-marriage equality, and who are anti-choice, and I do not believe this reflects the views of the membership.”

Ms Pratt said Labor factions had ridden rough-shod over the rest of the party and over the WA leader’s ability to make the right decision for pre-selections and on policy as well.

The exertion of such power by so few within the party was eroding public trust in the ALP, she warned.

“This is especially the case here in WA where ordinary branch members represent just a fraction of the overall state executive in lower house pre-selections and have no representation at all in Senate preselections.”

“WA is significantly behind other states when it comes to democracy in the Labor Party. We are the least democratic of all the nation’s ALP branches.

“This creates a lack of public trust … [which] has undermined our ability to win elections.”